Method of producing crushed high-loft,nonwoven material,including card and breaker frame blending

ABSTRACT

A high-loft, nonwoven fabric with a substantially continuous backing layer of adhesive and a multiplicity of fibers looped outwardly from the backing, with the fiber loops being at least partially crushed; and a method of making the fabric by first embedding a web of fibers in an open pattern of adhesive and then consolidating the adhesive into a substantially continuous backing layer while looping the fibers outwardly from the backing and crushing the loops. Variation of the appearance and color of the fabric may be achieved by blending fibers of various colors prior to, and during the forming of fiber slivers used in producing the fiber web, as well as verying the amount of crushing of the loops formed during the consolidation step.

- 1972 R. J. STUMPF METHOD OF PRODUCING CRUSHED HIGH 3.1053065 LOFT,NONWOVEN MATERIAL, INCLUDING CARD AND BREAKER FRAME BLENDING 9Sheets-Sheet 1 Filed OCt. 5, 1970 .mi w

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R. J. STUMPF 3,705,065 METHOD OF PRODUCING CRUSHED HIGH-LOFT, NONWOVENMATERIAL, INCLUDING CARD AND BREAKER FRAME BLENDING Dec. 5

9 Sheets-s 2 Filed Oct, 5 1970 F 3,705,065 IGH-LOFT, uouwovm:

L, INCLUDING CARD AND KER FRAME BLENDING 5, 1972 R. J. STUMP METHOD OFPRODUCING CRUSHED H MATERIA BREA 9 Sheets-Sheet 3 Filed Oct. 5, 19701972 R. J. STUMPF 3,705,065

METHOD OF PRODUCING CRUSHED HIGH-LOFT, NONWOVEN MATERIAL; INCLUDING CARDAND BREAKER FRAME BLENDING Filed Oct. 5, 1970 9 Sheets-Sheet &

I R. .1. STUMPF 3,705,065 METHOD OF PRODUCING CRUSHED HIGH-LOFT,NONWOVEN Dec. 5, 1972 MATERIAL, INCLUDING CARD AND BREAKER FRAMEBLENDING 9 Sheets-Sheet 5 Filed Oct. 5, 1970 R. J. STUMPF 3,705,065METHOD OF PRODUCING CRUSHED HIGH-LOFT, NONWOVEN MATERIAL, INCLUDING CARDAND BREAKER FRAME BLENDING Dec. 5, 1972 Filed Oct. 5, 1970 9Sheets-Sheet 6 Dec. 5, 1972 Filed Oct. 5, 1970 R. J. STUM PF I 3,705,065

METHOD OF PRODUCING GRUSHED HIGH-LOF'L, NONWOVEN MATERIAL, INCLUDINGCARD AND BREAKER FRAME BLENDING 9 Sheets-Sheet -71 Dec. 5, 1972 R. J.STUMPF 3,705,065

- METHOD OF PRODUCING GRUSHED HIGH-LOFT, NoNwovEN MATERIAL, INCLUDINGCARD AND BREAKER FRAME BLENDING Filed Oct. 5, 1970 9 Sheets-Sheet 8 Dec.5, 1972 R. J. STUMPF 3,705,065

METHOD OF PRODUCING CRUSHED HIGH-LOFT, NONWOVEN MATERIAL, INCLUDING CARDAND BREAKER FRAME BLENDING Filed Oct- 5, 1970 9 Sheets-Sheet 9 UnitedStates Patent O METHOD OF PRODUCING CRUSHED HIGH-LOFT,

NONWOVEN MATERIAL, INCLUDING CARD AND BREAKER FRAME BLENDING Robert J.Stumpf, Appleton, Wis., assignor to Kimberly- Clark Corporation, Neenah,Wis. Filed Oct. 5, 1970, Ser. No. 78,005 Int. Cl. D04h 11/00 US. Cl.156-72 16 Claims ABSTRACT OF THE DISCLOSURE A high-loft, nonwoven fabricwith a substantially continuous backing layer of adhesive and amultiplicity of fibers looped outwardly from the backing, with thefilber loops being at least partially crushed; and a method of makingthe [fabric by first embedding a web of fibers in an open pattern ofadhesive and then consolidating the adhesive into a substantiallycontinuous backing layer while looping the fibers outwardly from thebacking and thereafter reactivating the adhesive backing and crushingthe loops. Variation of the appearance and color of the fabric may beachieved by blending fibers of various colors prior to, and during theforming of fiber slivers used in producing the fiber web, as well asvarying the amount of crushing of the loops formed during theconsolidation step.

RELATED APPLICATIONS Robert J. Stumpf, Ser. No. 769,959, filed Oct. 23,1968,

now abandoned and replaced by Robert J. Stumpf, Ser.

DESCRIPTION OF THE INVENTION The present invention relates in general tononwoven fabrics and, more particularly, to methods for making improvedhigh-loft, nonwoven fabrics and to products formed by such methods Inrecent years, many different types of nonwoven ma terials have beenproduced, both to replace conventional woven fabrics and, also, tocreate new markets in which woven fabrics have not yet becomeestablished. This is particularly true in the case of materials forsingle-use and disposable products, such as: sanitary supplies, hospitalgarments, disposable sheets, and the like. For these applications thenonwoven fabric is generally made in continuous sheet form with one ormore layers of staple length fibers and/or a reinforcing scrim structureadhesively bonded together or laminated between plies of other materialsuch as cellulosic wadding and plastic sheeting. The fibers may benatural, synthetic or various blends and, of course, the particularcomposition of the nonwoven fabric is greatly influenced by its intendeduse.

Exemplary of such nonwoven fabrics are those disclosed in US. PatentNos. 2,902,395, 3,047,444, 3,072,511, 3,327,708, 3,484,330, 3,553,064and 3,553,065 and the aforesaid copending United States patentapplication, Ser. No. 79,287, which is assigned to the same as-3,705,065 Patented Dec. 5, 1972 signee as the present application. Whilethe products disclosed in the foregoing issued patents and copendingapplications have many different attributes and characteristics, theyall have one thing in common-viz, the principal fibers are nearly alldisposed substantially parallel to the surfaces of the nonwovenmaterial. As a result, the material is either relatively thin and flator, such substantial thickness and surface texture as are imparted tothe fabric are provided by creeping or embossing various layers of thematerial or, in some instances, the final nonwoven fabric.

It is also well-known that natural fibers, particularly cotton and wool,have an inherent kink or crimp resulting from the way in which thesefibers grow. This natural crimp is, of course, highly beneficial andcontributes largely to the strength of thread made of a multiplicity ofstaple length fibers. In addition, it is the natural crimp of thesefibers that imparts certain characteristics of texture and body tomaterials Woven therefrom.

In contrast, synthetic fibers, as initially formed, do not have anyappreciable kink or crimp since they are generally formed in continuousmonofilaments. However, it is also well-known that most synthetic fiberscan be crimped and heat-set by passing the fibers through a heatedstuffing box.

It is a primary aim of the present invention to provide a method ofmaking a nonwoven material which differs from the above and which ischaracterized by the simultaneous looping of a large number of fibersand the incorporation of the thus looped fibers into a nonwoven fabricwith the fibers extending outwardly from the backing material, andthereafter at least partially crushing or flattening the fiber loops toproduce a novel high-loft fabric with a pleasing surface texture andappearance.

It is a more particular object to provide a simple, economical, highspeed production method of making a novel, high-loft, nonwoven fabricfrom a Web of fibers having an open adhesive pattern previously printedon one side, by consolidating the adhesive into a substantiallycontinuous backing layer while simultaneously looping the fibersoutwardly from the adhesive backing and thereafter at least partiallycrushing the outwardly extending loops, either in preselected areas orthroughout the complete surface area of the fabric.

Another object of the invention is the provision of a method forproducing a novel, high-loft, nonwoven fabric, and a fabric producedthereby, wherein the crushing of the outwardly extending loops impartsan appearance to the fabric that resembles a woven crushed velvetfabric.

A further object of the present invention is the pro- 'vision of a novelnonwoven fabric and a method of producing the same in which the color ofthe fabric may be muted or dulled by increasing the amount of loopcrushing or flattening.

Yet another object of the present invention is to provide a method forproducing the above described fabric wherein fibers from supplies ofvarious colors may be blended prior to the forming of fiber silverswhich are used in making the fiber web.

Still another object of the present invention is a method whereby thesilvers may be combined in predetermined patterns to form groups ofsilvers that have a dominant color for use in producing the fiber web.

Another related object of the present invention is a method whereby theends of silver groups may be tied to the ends of other silver groupshaving another color so that the color of the fiber web is changed inthe machine direction.

Yet another object of the present invention is to combine the groups ofsilvers in a predetermined pattern during the formation of the fiber webwhereby the web has a predetermined design.

Other objects and advantages of the present invention will become morereadily apparent upon reading the following detailed description andupon reference to the attached drawings, in which:

FIG. 1 is a schematic view, in side elevation, of one form of apparatuswhich may be employed to produce a high-loft, nonwoven fabric;

FIG. 2 is a fragmentary plan view of an illustrative web of basematerial while still supported on a conveyor belt, somewhat simplifiedand exaggerated for the sake of clarity of illustration, with portionsbroken away to expose the various layers;

FIG. 3 is a fragmentary plan view of one embodiment of the product madeby the apparatus of FIG. 1;

FIGS. 4 and 5, respectively, are greatly enlarged, simplified, andsomewhat exaggerated sectional views taken substantially along the lines4-4 and 55 in FIG. 3;

FIG. 6 is an enlarged schematic detail view, "in side elevation, of theforming drum and gathering blade of the apparatus shown in FIG. 1;

FIG. 7 is an enlarged schematic side elevational view illustrating, insomewhat idealized fashion, successive stages in the sequence ofgathering and looping of individual fibers;

FIG. 8 is an enlarged schematic fragmentary view, taken substantiallyalong the line 8-8 of FIG. 7, here showing a fragment of the fiber weband adhesive pattern with illustrative fibers attached to the adhesive;

FIG. 9 is a simplified schematic view, taken substantially along theline 99 of FIG. 7, here showing the fragment of the fiber web andadhesive pattern depicted in FIG. 8 at a later stage in the loop formingsequence;

FIG. 10 is a schematic view, in side elevation, of one form of apparatusthat may supplement the apparatus shown in FIG. 1, and is adapted toapply a second pattern of second adhesive upon the first pattern ofadhesive;

FIG. 11 is a fragmentary plan view of an illustrative web of basematerial having two applications of adhesive, the view being somewhatsimplified and exaggerated for the sake of clarity of illustration, withportions broken away to expose the various layers;

FIG. 12 is a greatly enlarged, simplified and somewhat exaggeratedsectional view taken substantially along the line 12-42 of FIG. 11;

FIG. 13 is a schematic view, in side elevation, of exemplary apparatuswhich may be employed to at least partially flatten or crush the loopsextending outwardly from the backing layer of the fabric;

FIG. 14 is a diagrammatic illustration of exemplary apparatus that maybe used to form the fiber web that is applied to the adhesive pattern;

FIGS. 1 5-18 illustrate, in plan view, exemplary alternative adhesivepatterns that may be used for the base web in practicing the method ofthe present invention;

FIGS. 19 and 20, respectively, are photographic reproductions of afabric produced by the apparatus of FIG. 1, illustrating a crosssectional view in the machine direction and enlarged l3 and 50 times;

FIG. 21 is a photographic reproduction of a cross section in the machinedirection, enlarged 13 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 100 p.l.i.;

FIG. 22 is a photographic reproduction of a cross sec- .tion in thecross direction, enlarged 13 times, and illustrating a fabric havingbeen subjected to a nip pressure of approximately 100 p.l.i.;

FIG. 23 is a photographic reproduction of a cross section in the machinedirection, enlarged 50 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 100 p.l.i.;

FIG. 24 is a photographic reproduction of a cross sec- .tion in thecross direction, enlarged 50 times, and illustrating a fabric havingbeen subjected to a nip pressure of approximately 100 p.l.i.;

FIG. 25 is a photographic reproduction of a cross section in the machinedirection, enlarged 13 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 190 p.l.i.;

FIG. 26 is a photographic reproduction of a cross section in the crossdirection, enlarged 13 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 190 p.l.i.;

FIG. 27 is a photographic reproduction of a cross section in the machinedirection, enlarged 50 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 190 p.l.i.;

FIG. 28 is a photographic reproduction of a cross section in the crossdirection, enlarged 50 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 190 p.l.i.;

FIG. 29 is a photographic reproduction of a cross section in the machinedirection, enlarged 13 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 190 p.l.i.;

FIG. 30 is a photographic reproduction of a cross section in the crossdirection, enlarged 13 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 250 p.l.i.;

FIG. 31 is a photographic reproduction of a cross section in the machinedirection, enlarged 50 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 250 p.l.i.; and

FIG. 32 is a photographic reproduction of a cross section in the crossdirection, enlarged 50 times, and illustrating a fabric having beensubjected to a nip pressure of approximately 250 p.l.i.

While the invention is susceptible of various modifications andalternative forms, specific embodiments thereof have been shown by wayof example in the drawings and will herein be described in detail. Itshould be understood, however, that it is not intended to limit theinvention to the particular forms disclosed, but, on the contrary, theintention is to cover all modifications, equivalents and alternativesfalling Within the spirit and scope of the invention as expressed in theappended claims.

THE ENVIRONMENT OF THE INVENTION In practicing the method of the presentinvention in its preferred form, a base web of fibers is first preparedand an open adhesive pattern is applied to one side of the web.Different procedures have been used in preparing the base web. Forexample, textile length fibers may be processed through conventionalcotton card machinery to produce a carded web for the base web. In sucha carded web 50% to 70% of the fibers may be oriented substantiallyparallel with the machine direction. It has been found, however, thatthe most uniform product has been obtained with the method of thepresent invention by using base webs having a higher percentage of thefibers alined with the machine direction such, merely by way of example,as a highly drafted web in which, as a result of the drafting process,to of the fibers may be alined with the machine direction. Such Webs ofbonded, highly drafted fibers, of course, have substantial utility inthemselves and are the subject, for example, of the aforesaid copendingapplication, Ser. No. 79,287, US. Patent No. 3,553,065. The presentinvention, however, goes far beyond the preparation of adhesively bondedcarded webs or the products and methods disclosed in those twoapplications; and results in the formation of a high-loft, nonwovenfabric having significantly different characteristics than the nonwovenweb utilized as the base material.

Broadly stated, the method of the present invention in volves taking thebase material and performing the subsequent steps of: (1) reactivatingthe open pattern of adhesive in which the fibers are embedded; and, (2)consolidating the adhesive into a substantially continuous backinglayer, while (3) simultaneously looping the portions of the fibersacross the open spaces of the adhesive outwardly from the backing layerformed by the consolidated adhesive, and (4) thereafter at leastpartially crushing or flattening the loops under controlled conditions.The resulting product is characterized by the high loft or deep pile ofthe loops of fibers which extend outwardly from the adhesive backing,but which have been at least partially flattened to give the surfacetexture a unique appearance which may resemble the appearance ofconventional woven crushed velvet fabric. The particular depth of pileor degree of loft of the loops, of course, depends upon a combination ofcontrol parameters including, for example; the type and denier of thebase fibers; the amount of spacing of the original adhesive patterns;the angle of the gathering blade; the relative speeds of fiber deliveryto and fabric discharge from the gathering blade; and the amount ordegree of flattening or crushing of the fiber loops; as will bediscussed below.

In addition, the present method also contemplates, in some instances,additional steps, such as: applying a second pattern of adhesiveoverlying the first pattern of applied adhesive; and, blending togetherfibers of different colors during the formation of the striated fiberweb in one or more of four separate steps, which are: 1) mixing fibersfrom one or more supplies of fibers of various colors prior to cardingor otherwise forming the individual fiber slivers; (2) combining thefiber silvers into groups of slivers in a preselected pattern to imparta dominant color to each of the groups of slivers; (3) combining thegroups of slivers having a dominant color in a predetermined pattern toimpart a design to the fiber web that is subsequently applied to theopen pattern of adhesive; and, (4) tying groups of slivers to differentcolored groups to change the color of the fiber web in the machinedirection. These additional steps will also be discussed in detailbelow.

Turning now to the drawings, before describing the novel high-loft,nonwoven fabric effected by the present invention, it is important todescribe the basic method of producing a high-loft, nonwoven fabric uponwhich the present invention is intended to improve. This particularmaterial, and the process by which it is made, will be described in somedetail herein so that the improved properties provided by the presentinvention can be fully appreciated and understood. Both the material andthe process for producing the same are described in even more detail inthe copending applications cross referenced above, all of which areassigned to the assignee of the present invention.

Thus, the high-loft nonwoven material employed in the present inventionis preferably prepared by the method and apparatus, schematicallyillustrated in FIG. 1. This apparatus includes a web forming section andan adhesive compacting and fiber looping section 30. The web formingsection 10 is generally similar to the apparatus disclosed in theaforesaid copending application, Ser. No. 79,287, with certainmodifications as disclosed in the aforesaid US. Patent No. 3,553,065,but it is here shown in more complete and visible form than shown ineither of those disclosures. It will be appreciated as the ensuingdescription proceeds, that fiber webs made in accordance with the methoddisclosed in the aforesaid copending application, Ser. No. 79,287, arealso usable with the subsequent method steps for producing thehereinafter described fabric, as are carded webs and webs prepared byother processes.

As shown in FIG. 1, multiple slivers 11 of textile fibers are drawn fromtheir respective supply cans (not shown) into a draw frame 12 whichcomprises a series of pairs of grooved rolls 13; the rolls of each pairbeing driven by appropriate gearing (not shown, but well known in theart) at a peripheral rate of speed somewhat faster than the rate ofoperation of the preceding pair. Merely by way of example, the pairs ofrolls 13 may be adjusted to provide an over-all increase in speed and,therefore, an extent of fiber draw on the order of 15:1 through the drawframe 12. As the juxtaposed slivers pass through draw frame 12, theindividual fibers are drafted and spread out to form a fiat, striatedweb of substantially alined fibers as shown at 14. Web 14 is maintainedadjacent a supporting conveyor sheet 15 on the surface of which adhesivehas been previously applied in a preselected pattern.

In this embodiment, the conveyor sheet 15 comprises an endless conveyorbelt treated on at least its upper surface with a release agent. Oneexample of such a belt comprises woven glass fiber with a surfacecoating of tetrafluoroethylene resin. Other examples of release coatingsare well known, and comprise such materials as silicones, fatty acidmetal complexes, certain acrylic polymers, and the like. Heat resistantfilms or thin metal sheets treated with release agents may also be usedas the carrier sheet.

Prior to the time the web 14 is picked up by the belt 15, the latter hasimprinted on its release-treated surface a pattern of flexible,thermoplastic adhesive such as is shown at 16 in FIG. 2. It will beunderstood that, as shown in FIG. 1, the adhesive is actually on theunderside of belt 15 which becomes the upper surface after passingaround roll 17, at which time the adhesive pattern 16 directly contactsthe fiber web 14. The pattern is shown as being visible in FIG. 2 onlyfor illustrative purposes.

The belt 15 is fed around roll 17 at a speed slightly in excess of thedelivery speed of the final pair of rolls 13 of draw frame 12 in orderto maintain web 14- under slight tension, whereby the individualhighly-drafted fibers are retained in their alined and tensionedcondition. Drive rolls 18, 19 are rotated (by suitable drive means, notshown) to drive belt 15 at a speed sufficient to maintain the propertension on the web '14.

In the method shown for applying adhesive, the belt 15 is fed through ahip formed between a printing roll 20 and a back-up roll 21 maintainedin very light pressure engagement therewith. The surface of printingroll 20 is provided with an intaglio pattern to which adhesive may besupplied in various ways well known to those skilled in the art. Forexample, in the aforesaid parent application, Ser. No. 769,959, a systemis schematically disclosed wherein the lower portion of the printingroll 20 picks up adhesive directly from a dip pan, with excess adhesivebeing removed by a doctor blade, thus leaving only the intagliopatterned surface filled. However, it has been found that moresatisfactory results are obtained by pumping or otherwise transferringadhesive 22 from a supply pan 23 to a reservoir located immediatelyabove an inclined doctor blade 24-the reservoir being defined in part bythe upper surface of the inclined doctor blade and the adjacent portionof the rotating peripheral surface of the printing roll 20. Thus, as theprinting roll 20 rotates (in a counterclockwise direction as viewed inFIG. 1), the intaglio patterned surface thereof is filled with adhesive22, excess adhesive is removed by the doctor blade 24, and a meteredamount of adhesive is then transferred to the underside of releasecoated belt 15 in a preselected pattern. The pattern shown in FIG. 2 isin the form of an open diamond pattern of adhesive.

The particular dimensions of the intaglio pattern employed and, indeed,the actual pattern itself, are not critical to the practice of theinvention in its broadest aspects. Thus, it has been found that patternsother than the illustrative diamond pattern hereinabove referred to canbe utilized, and certain of such patterns will be subsequently describedin connection with FIGS. 15-18. For illustrative purposes, however, itis noted that excellent results have been achieved where a diamondpattern was employed in which adjacent lines of adhesive were spacedapart in both directions by A, and wherein the intaglio printing roll 20had adhesive cells or lines 0.007 deep and 0.025 wide.

Since the surface of belt 15 is treated with a release coating, theadhesive remains substantially on the surface with no-penetrationtherein and is preferably in a somewhat tacky condition. The printedbelt is drawn from the printing nip around roll 17 positioned closelyadjacent the output end of draw frame 12 and, as stated above, at aspeed slightly in excess of the delivery speed of the last two rolls inthe draw frame. The web 14 emerging from the draw frame 12 is depositedon the tacky adhesive 16 on belt 15 and held in tensioned engagementtherewith by the adhesive and the above-mentioned speed differential.This continuous tension prevents the fibers in the web from losing theirhighlydrafted and alined condition.

In practicing the method, additional alined and highlydrafted fibers maybe added to the web 14 on the adhesively printed belt 1'5. For thispurpose, a second draw frame 25 similar to the draw frame 12 is providedto draw additional slivers 26 of fibers from their supply cans (notshown) and, after drafting and alining them, to deposit the fibers onthe moving web 14 carried by the belt 15. In such cases, the amount ofadhesive printed on the belt 15 may be increased to insure that some ofthe adhesive in the adhesive pattern 16 penetrates the fibers of web 14drawn from the draw frame 12 and reaches the fibers drawn from slivers26 which pass through the second draw frame 25. The arrangement is suchthat the adhesive contact between the fibers drawn from slivers 26 andthe pattern 16, together with the speed differential of the belt 15relative to the last pair of rolls in the draw frame 25, maintains thefibers drawn from slivers 26 under slight tension, whereby they alsomaintain their highly-drafted and alined condition.

The fibers deposited on the web 14 from draw frames 12 and 25 need notbe the same kind, size, color or quantity. Nor, for that matter, do thefibers of the slivers '11 and 26 need to be uniform in these respects asthey are drawn into the draw frames 12 and 25. Thus, various blends offiber sizes, kinds, colors and quantities can be deposited across theweb 14 from each of the draw frames 12 and 25 and in variouscombinations of first and second layers of fibers. Additional drawframes can also be employed if desired.

The fibers from each of the draw frames 12 and 25 pass under respectivebars 27 and 28* before being de posited on the belt 15. The bars 27, 28may be oscillated in a direction generally transverse to the movement ofthe web 14 and, preferably, provision is also made for controlling thefrequency and amplitude of the oscillation of one bar relative to theother. Thus, as each bar is oscillated, the fibers deposited from therespective draw frames 12 and 25 take on a generally sinusoidal orsawtooth wave pattern of controlled frequency and amplitude. A simple,but somewhat similar, oscillating bar arrangement is disclosed in theaforesaid US. Pat. No. 3,553,065. However, the single bar arrangementthere disclosed did not afford, nor even contemplate, the significantlyimproved attributes made possible by this method.

'An example of the web 14 formed on the illustrative apparatus (FIG. 1)is shown in FIG. 2. As previously mentioned, a series of parallel anddiagonally disposed lines of adhesive are printed in criss-cross fashionon the belt to form a pattern 16 of adhesive having substantially openspaces in the configuration of diamonds. In depositing the fibers fromthe first draw frame 12, the bar 27 was not, in this instance,oscillated. Thus, the fibers making up the first component 14a of theweb 14 are substantially all alined in the direction of web movement.The fibers making up the second component 14b of the web, however, willbe seen to be deposited in a generally wavy or saw-tooth pattern as aresult of oscillation of the bar 28 associated with the second dralwframe 25, thus altering the appearance characteristics of the finishedfabric. In addition, oscillation of the bars 27 and/or 28 serves toalter the structural and functional characteristics of the fabric inthat a controllable percentage of the fibers may be deposited on theopen adhesive pattern at an angle to the machine direction. It has beenfound that such fibers do not interfere to any significant extent withthe subsequent fiber looping steps. Moreover, it is believed that thepresence of such fibers extending at an angle to the machine directionserves to increase the cross-directional strength of the fabric beingproduced by actually increasing the number of oriented fibers whichextend partially in the fabric cross-direction. Preferably, when bothbars 27 and 28 are oscillated they are oscillated in out-of-phaserelation to one another so as to cause fibers in one web component 14ato cross fibers in the other web component 1412 at even greater angleswhile simultaneously maintaining the fibers in a highly oriented state.It will, of course, be understood that the phase and amplitude of theoscillated fiber pattern may be selectively adjusted and controlled toprovide a controlled angular deposition of fibers on the open adhesivepattern 16, thus enabling control of the cross-directional strengthcharacteristics of the fabric resulting from fiber oscillation. Thiswill, of course, vary dependent upon various other parameters such, forexample, as the type of fibers employed, the type of adhesive employed,fiber-adhesive ratios, gathering ratios, and indeed, the particular enduse to which the fabric is to be put. Consequently, in many instances itmay not be desirable to oscillate either bar 27 or 28. It should beappreciated, of course, that FIG. 2 is only intended to be illustrativeand, while the lines representing the fibers for both components 14a and14b are spaced apart for clarity, in practice the highly-drafted fibersof both components are very close to one another.

Also for illustrative purposes, it will be noted that web component 14bhas three bands of fibers designated color. These bands of fibers may bethe same or different colors but, in any event, they differ from thecolor of the balance of the fibers of web component 14b. Further, aspreviously mentioned, the fibers of web component 14b may differ fromthose of component 14a in 'kind, size, color or quantity depending uponthe desired color pattern and surface characteristics of the finalproduct, as more specifically described 'below.

Following deposit of web components 14a and 14b on the adhesive printedbelt 15, the belt is drawn around a heated curing drum 29 where fusingand curing of the adhesive is substantially completed while the web 14is maintained in firm contact therewith to bond the individual fibers.To insure effective heating and fusing of the adhesive, it is desirablethat travel of the combined belt and web be around a substantial portionof the drum 29. In the illustrated embodiment, a fly roll 29a ispositioned to apply tension on the combined belt and web as they travelaround the drum 29 to insure complete embedment of the fibers in theadhesive. The fibers of the web 14. are thus bonded together whileretaining their highly-drafted and substantially alined condition in theparticular pattern in which they were deposited on the open pattern ofadhesive 16 printed on the belt 15.

After leaving the fly roll 29a, the combined web 14 and belt 15 arepreferably passed over the drive roll 19, which also serves as a coolingdrum to set the adhesive. The bonded web 14 is stripped from therelease-coated surface of the belt 15 by the guide roll 31 as the webleaves the cooling drum 19.

While various well-known adhesives may be employed in the foregoingprocess, advantages reside in the use of plastisols, which are colloidaldispersions of synthetic resins in a suitable organic ester plasticizer,and which, under the influence of heat, provide good binding power whileremaining soft and flexible. While many adhesives of this type areknown, those found particularly useful for incorporation in the productof this invention include vinyl chloride polymers, and copolymers ofvinyl chloride with other vinyl resins, plasticized by organicphthalates, sebacates, or adipates. These provide a fast curingplastisol adhesive characterized by relatively low viscosity, lowmigration tendencies, and minimum volatiltiy. Such adhesives remain softand flexible after curing, and can be reactivated by subsequent heating.

It has been found that other adhesives may be employed in the processforexample, organisols utilizing resins such as the vinyl chloride polymersand copolymers. Furthermore, still other adhesives may be employedprovided that they satisfy specified characteristics in the base webproduced in the web forming section 10, and in the finished fabricproduced in the adhesive compacting and fiber looping section 30 (FIG.1). In general, such adhesives should be applied to the base web byprocedures which will not disarrange the fibrous structure of the web;such adhesives should heat-set at temperatures below the degradationtemperature of the fibers in the base web 14 to secure bonding of thefibers to the adhesive; such adhesives should be reactivatable in thesubsequent adhesive gathering and consolidation stage of the process;and such adhesives should form a flexible backing layer for the finishedfabric and should strongly bond the fiber loops in place. For example,emulsions of thermoplastic resins such as acrylics and rubber-likecompounds, illustratively ABS, have the requisite properties to serve asthe bonding adhesive for the web 14- The base material, made asheretofore described and comprising a web 14 of highly-drafted fibersembedded in an open adhesive pattern, is fed into the adhesiveconsolidating and fiber looping section 30 of the apparatus shown inFIG. 1. As shown here, the Web 14 continues directly from the webforming section to the consolidating and looping section 30. It shouldbe appreciated, however, that the web 14 discharged from section 10could be rolled up for storage or transport and then subsequentlyunrolled and fed into section 30. Also, as previously mentioned, otherwebs such, merely by way of example, as those made in accordance withthe methods disclosed in the aforesaid copending application Ser. No.79,287 and US. Patent No. 3,553,065, can be further processed in section30.

As illustrated in FIG. 1, the Web 14, while still under tension, is fedaround an idler roll 32 and on to the surface of a heated forming drum37. In its preferred embodiment, the drum 37 is made of metal with ahighly polished, chromium plated surface which is heated and maintainedat a temperature of approximately 250 F. Also, the web 14 is arranged totravel a substantial distance around the drum 37 with the open patternof adhesive 16 in contact with the heated drum surface. As the web 14 isfed onto the drum 37, the heat from the drum surface reactivates andsoftens the adhesive printed on the underside of the web, causing it tobe tacky and to adhere slightly to the drum surface, thereby maintainingthe web under constant tension. The drum temperature, which ismaintained at about 250 F., is, however, maintained below the meltingpoint of the adhesive to prevent dispersion of the adhesive into thefibers of the Web.

The web 14 of fibers and softened adhesive is reformed by thecooperative action of the drum 37 and a gathering blade 38 having a flatedge 39. The blade edge 39 operates to consolidate the open adhesivepattern 16 into a substantially continuous backing layer of adhesive,while simultaneously looping the fibers of the web outwardly frombetween the open spaces in the original adhesive pattern. The reformedand consolidated material 40 then leaves the blade edge 39 and movesonto a flat take-off surface 41 and a discharge conveyor 52.

Turning now to FIGS. 7-9, the method of making the novel high-loft,nonwoven fabric 40 will be explained in greater detail in connectionwith an illustrative sequence of the gathering and looping of a singlefiber of the web 14 and the consolidation of its two original points ofadhesive attachment in the pattern 16. As seen in FIG. 8, the fiber hasa portion P which extends across the open space of the diamond patternof adhesive 16 from point A to point B where it is embedded in theadhesive. Referring to FIG. 7, the series of views in this figureillustrates how the portion P of the fiber is formed into a loop; viz,when point A being carried around the heated drum 37 impinges againstthe gathering blade edge 39, its forward motion is halted and it isscraped along the surface of the drum, while point B continues toadvance with the drum surface since, due to its softened and tackycondition, it adheres to the smooth drum surface. As point B advancesrelative to point A, the portion P of the fiber between points A and Bis caused to bow outwardly from the drum surface. Finally, point Bovertakes point A and these points of adhesive are substantiallyconsolidated as seen in FIG. 9. In the meantime, fiber portion P hasbeen looped outwardly from the drum surface.

It will, of course, be understood that while looping of fiber portion Pis occurring, additional adhesive points CD, etc., traveling around thedrum 37 impinge against the gathering blade edge 39 causing aconsolidation of these adhesive points and looping of their intermediatefiber portions P as is also indicated in FIG. 9. This occurssimultaneously at all points across the web at the blade edge, producinga substantially continuous backing layer of adhesive from which extendsthe multiplicity of loops formed by the fibers of the base web. The thusformed substantially consolidated layer of adhesive is carried away fromthe blade edge 39 along the take-off surface 41 and provides asubstantially continuous backing layer for the outwardly looped fibers,thus producing the fabric 40.

While in the preferred form, it is desired to achieve substantiallycomplete consolidation of the adhesive into a continuous backing layer,in practice it has been found that the degree of consolidation variesrandomly throughout the substantially continuous backing and, therefore,it is possible to draw the fabric slightly, thus producing asubstantially continuous adhesive backing layer with random openingstherethrough. 'Since complete consolidation, while desirable, is notnecessarily attained in practice, the degree of consolidation is definedherein, and in the appended claims, in terms such as to consolidate theopen adhesive pattern into a substantially continuous adhesive layer.Thus, those skilled in the art will appreciate that terms such asconsolidate as used herein and in the. appended claims are intended toconnote an arrangement for consolidating or compacting the open adhesivepattern into a substantially continuous adhesive backing layeralbeitthat such substantially continuous backing may have, and often willhave, small random fissures and gaps therein-all as distinguished fromthe arrangement disclosed in the aforesaid copending application, Ser.No. 820,224, wherein the open adhesive pattern is only partiallyconsolidated to minimize bonding of adjacent lines of adhesive and thusform a discontinuous adhesive backing layer characterized by itselasticity and/or stretchability.

Another important feature is that not only does each fiber portion Ploop outwardly from the drum surface but, also, as the loop is formed itturns, reaching a position in the fabric 40 generally perpendicular tothe direction of the original alinement of fiber portion P. Thus, thefiber loops arrange themselves so that the plane of each loop issubstantially normal to the original fiber alinement shown in FIG. 8.The reason for the loop twisting as it is formed may be explained bythis observation. If two spaced points of a single fiber not in a webare brought together, it has been observed that the fiber will form aloop and, as the loop is formed, it twists towards a position of minimuminternal stress, turning through an angle which tends to approach Incarrying out the methd, because of the great number of fibers in the weband their proximity one to another, each fiber loop engages theneighboring fiber loops with the result that all the loops are blockedfrom turning beyond the plane "substantially normal to the machinedirection, and are constrained in that position by the interferencebeween the loops. In practice, of course, the actual direction anddegree of loop twist depend upon the characteristics of the fibers inthe original web 14.

It is important to note, however, that throughout the fabric the heightsof the fiber loops vary according to the spacing between the points ofattachment of each fiber to the open adhesive pattern in the base web.Referring to FIGS. 4, 8 and 9', it will be seen, for example, that theloop formed by the fiber portion P between the points of adhesiveattachment C, D will have a lower height than the loop formed by thelonger fiber portion P between the points A, B. On the other hand,however, successive loops in adjacent diamonds, when viewed in avertical section taken along the machine direction (FIG. will have thesame height since the fiber length P will remain the same betweensuccessive sets of points A, B. This results in a dense fabric with thelower loops supporting and filling around the higher loops and the topsurface of the fabric being formed by the tops of the higher loops.

The appearance of a fabric so constructed depends not only on the heightof the fiber loops but, also, on the type and denier of the fiber usedin the base web, and one of the features of the invention is that thedepth of the fabric and the evenness of the surface may be varied byadjusting selected ones of the control parameters, as will be explainedbelow. In general, it may be said that for both relatively low andmoderate height high-loft materials which have been produced with themethod of this invention, the fabric appears to have a uniform thicknesswith a somewhat uneven surface texture. With very deep high-loftfabrics, particularly those made from flexible, low denier fibers, thehigher loops tend to lay one over the other, thus providing a very soft,napped, fuzzy, fibrous surface.

To illustrate the effect of varying one of the control parameters, inthis case, the angle of the edge of the blade 38 relatives to the drum37 will now be described. Referring to FIG. 6, it will be seen that theblade edge 39 forms an angle a with the line T tangent to the surface ofthe drum 37. It has been found that the blade edge angle a is oneparameter that determines the depth of the fabric produced and thedegree of uniformity of consolidation of the adhesive backing layer.

As a result of trying different blade angles, it has been determinedthat the preferred blade edge angle on when dealing with adhesivepatterns having lines of adhesives spaced approximately A" apart isbetween about 17 and about 34. With blades having edge angles withinthis preferred range, fabrics have been produced which are characterizedby having a high degree of uniformity of consolidation of the adhesivebacking layer which is substantially void of fissures or gaps and, byhaving a dense, regular mass of loops that provide a textured, somewhatuneven surface.

With blades having edge angles a less than 17 difficulty has beenexperienced in obtaining a uniformly consolidated adhesive backinglayer. This appears to be the result of insufficient relief between theblade edge and the drum surface for the fabric to flow evenly andsmoothly off the drum surface as the result of the action of the blade,which produces varying degrees of consolidation of the adhesive and anon-uniform layer with fissures and gaps and scattered areas where thelooping is irregular, tending to spoil the surface appearance of thefabric. With blades having edge angles a substantially above 34, boththe problem of non-uniform adhesive consolidation and poor loopformation has been experienced. There is also a tendency as the angle aof the blade edge is increased substantially above 34 for the 12 fabricto be formed with pronounced ridges, which may be undesirable in thefinished product.

In practice, it has been found that one of the major factors effectingthe thickness of the fabric is the loop height as determined and limitedby the spacing between points of fiber adhesive attachments A-B, C-D,etc. ('FIG. 8). To obtain the maximum thickness of fabric with a givenadhesive pattern, the blade edge angle a should be such as to producenot only sufficient consolidation of the adhesive layer to provide goodfiber attachment throughout the fabric but, also, sufficientconsolidation to insure the production of a maximum number of fullheight fiber loops. Thus, as the blade edge angle 04 increases, thecondition is approached where the web is being skived off the rollrather than being consolidated and gathered. The fabrics produced withhigher blade edge angles a have reduced adhesive consolidation andfabric thickness because fewer loops reach their maximum height.

When using a blade 38 having an edge angle or within the preferredrange, it has been found that the fabric loft may be regulated bychanging the machine direction dimension of the adhesive pattern. Thus,by increasing this dimension, the height of the loops may be increased,thereby increasing the fabric loft. Larger diameter fibers, strands, oryarns may also be used as the elements of the base web to produceheavier, carpet-like finished fabrics. The adhesive and its pattern ofapplication must, however, take into consideration the amount ofadhesive required to form the backing layer under the consolidatingaction of the gathering blade 38, and sufiicient adhesive must bepresent to provide a substantially continuous backing layer ofsufficient thickness to obtain strong attachment of the loops in thefinished fabric. More specific disclosures of types of adhesive patternssuitable for use in making carpet-like fabrics of larger diameterfibers, strands, or yarns may be found in the aforesaid copendingapplication of Herman G. Minshell, Robert J. Stumpf and William J.Mattes, Ser. No. 77,840, which is assigned to the assignee of thepresent invention.

Now turning to a consideration of a different control parameterviz., thelocation of the take-away surface 41--the preferred location of thetake-away surface is, as shown in the extreme right-hand view in FIG. 7,tight against the blade 38 and even with the outside corner 39' of theblade. With the surface 41 in this preferred location, the fabric mayhave a moderately even surface texture and a dense mass of loops forminga deep, highloft pile.

It has been found that by lowering the take-away surface 41 a distance Y(FIG. 7) from its preferred location, the structure of the fabric willbe drastically affected, in that the bulk of the fabric may be increasedsubstantially by lowering the take-away surface 41. The effect oflowering the surface is somewhat similar to the effect from using ablade 38 with an edge angle a substantially above the preferred range inthat pronounced ridges are also produced in the fabric, therebyincreasing its bulk. The amount that the take-away surface is lowereddoes clearly effect the degree of bulking, and it is apparently the casethat as the distance Y increases, the fabric bulk increases.

A further related parameter that affects the gathering function of theblade is the take-away speed of the fabric from the blade edge. Withblade 38 having an edge angle oz within the preferred range, and atake-away surface at the preferred location, the take-away speed isdesirably regulated to remove the newly formed fabric at the rate atwhich it is being formed, and it has been found that under theseconditions the normal ratio of the surface speed of the heating drumfrom 37 to the takeaway speed will be about 12.1. By increasing theratio up to, for example, 15:1, by slowing down the fabric takeawayspeed, more uniform adhesive consolidation has been obtained while themass of the fiber loop is made somewhat more dense, so that a fabricwith a higher weigut 13 has been produced. By increasing the fabrictake-away speed, such that the fabric is not allowed to gather at theblade edge 39, the fabric will be drawn or extended while the adhesivelayer is still in a plastic condition, thereby opening the adhesivelayer, thinning the fabric pile, and reducing the weight of the finishedmaterial.

Thus, by selection of the blade edge angle on, takeaway ratio, and theheight of the take-away surface 41, the fiber looping, fabric pleatingplus bulk and basis weight of the fabric may be controlled to produce aproduct of desired characteristics.

Further parameters that affect adhesive consolidation and fiber loopingat the blade edge 39 are: (1) the adhesive pattern applied to the fibersin the formation of the base web 14; (2) the adhesive weight as apercentage of the weight of the web; (3) and the area of the web coveredby the adhesive pattern.

In addition to the diamond pattern, other adhesive patterns which may beused include unevenly spaced lines of application, such as criss-crossedsine waves 80 as shown in FIG. 15. The spacing of such lines of adhesivemay furthermore be increased or decreased to change the maximum heightof the element loops and, thus, the depth and surface texture of thefinished material.

When criss-crossed lines of adhesive are used, the loops of the fabricwill have varying heights due to the different spacings of the points ofattachment (A-B, C-D -FIG. 8) of the base web elements to the adhesive.To produce a fabric with loops of uniform height, the adhesive isapplied to the base web '14 in lines evenly spaced apart and extendingacross the web. Furthermore, the spacing between the lines of adhesivemay be increased or decreased to obtain a higher or a lower pile height,as desired. Referring to FIG. 16, one such adhesive pattern isillustrated in the form of evenly spaced diagonal lines 82. Another suchadhesive pattern is illustrated in FIG. 17, in the form of lines 84,each in the shape of a sine wave. A brick-like pattern is another suchpattern as shown in FIG. 18. If broken lines of adhesive are utilized toobtain element looping-such, for example, as the brick-like pattern ofFIG. l8 the gaps in the lines of adhesive 86 should be staggered so thatthe web elements longitudinally span the spaces between the adhesivelines and are securely attached to the adhesive.

When the spacing of points of attachment of the fibers to the adhesivevaries regularly over the area of the base web as, for example, when anopen diamond pattern of adhesive is used, the loops in the finishedfabric will vary in height in a regular manner to provide a uniformlyvarying surface having a textured appearance. When, on the other hand,an open pattern of adhesive is used in which, in the cross direction ofthe base web 14, the lines of adhesive are parallel, or evenly spaced,it will be seen that the spacing of points of attachment of the elementsto the adhesive will be uniform over the total area of the fabric, andthe loops in the finished fabric will be of uniform height to provide amore even surface. The appearance of such a surface will, of course, beaffected by the characteristics of the elements which form the loops.Thus, where the elements are yarn or heavy strands of fibers the loopswill be clearly visible, while where the elements are small diameter,flexible fibers, the surface will have a fibrous appearance, the fiberlooping being less evident.

It has been observed that the transverse adhesive lines, whenconsolidated by the action of the gathering blade 38, are moved intoproximity or abutment with each other and, being in a soft tacky statedue to the high temperature of the heating drum 37, tend to bond to eachother. However, the bond between lines of adhesive may be broken and theopen pattern of adhesive substantially restored by drawing the fabric inthe machine direction after the adhesive backing layer has been cooled,all as more clearly described in the aforesaid copending applicationSer. No. 820,224. It may thus be demonstrated 14 that the backing layer,while it appears to be continuous in the finishd fabric, actuallycomprises lines of adhesive extending in the cross direction of thefabric and bonded to each other.

In the application of the adhesive to the base web, it has been observedthat by increasing the adhesive viscosity, a sharp, distinct printedpattern will be obtained such that the fibers are securely attached tothe adhesive at distinct spaced points and are not embedded in adhesivethroughout their length. It is desired to have spaced points of fiberadhesive attachment so that the fiber loops will be distinctly andseparately formed at the gathering blade in such a manner as to extendoutwardly from the adhesive bonding layer. Fiber sizes between 1 /2denier and 15 denier have been successfully utilized in the base web 14with a inch diamond pattern of adhesive. With higher denier fibers, orwith strands or yarns used in the preparation of the base web, theadhesive pattern is preferably enlarged so as to insure attachment ofthe fibers or strands to the adhesive at spacings along the length ofthe threads or yarns which will define the depth of pile or degree ofloft in the finished material. With the lightweight webs of rayon theratio of fiber to adhesive is preferably approximately 1:1. It has beenfound that the degree of adhesive fiber attachment in the base web wasaffected when the fiber-to-adhesive ratio with such type fibers wassubstantially increased above 1:1, so that the fiber loops did not formproperly at the blade 38, nor did the fibers have sufficient attachmentto the adhesive layer in the finishd fabric. On the other hand,increasing the relative amount of adhesive in the base web had theresult of producing a thicker adhesive layer in the finished materialand more secure fiber attachment, but the adhesive lines tend todisperse so that the pattern becomes less open, thereby affecting theheight of the loops, which is undesirable. The fiber-adhesive ratio willbe different, however, for base webs of yarns and threads where itappears that less amounts of adhesive, relatively speaking, will provideadequate attachment of the loops to the adhesive backing layer.

While staple length rayon fibers may be used for the preparation of thefabrics, other fibers may also be used in the process in its preferredform, and have resulted in fabrics of excellent properties of hand,drape, and appearance.

For example, acrylic, olefin and polyester fibers have been used, and itis within the contemplation of the invention to use any or all of thesefibers by themselves or in blends, as well as natural fibers, acetate,nylon and other synthetic fibers in staple length or in monofilamentform, any of which may be used for the preparation of the base web =14.Moreover, not only highly drafted webs and carded webs of staple lengthfibers may be used for the base web, but, also, garneted and air-laidwebs of such fibers as well as directly laid alined webs ofmonofilament. It has been noted, however, that when webs such as cardedwebs are used for the base web in which an important proportion of thefibers are randomly oriented, those fibers not alined with the machinedirection appear to interfere with the loop production by the gatheringblade. The most regular formation of loops with the loops turned normalto the machine direction has been produced with those base webs havingthe highest proportion of fibers alined with the machine direction as,for example, the highly drafted webs made with the apparatus illustratedschematically in FIG. 1.

It is also contemplated that flexible threads, yarns or strands may beused for forming a base web, provided that the flexibility of suchelements is high enough to permit looping of the fibers and turning ofthe loops in the manner heretofore described. To obtain regular loops ofsuch elements in the finished material, it is clear that substantiallyall such elements should be parallel and extend longitudinally of theweb, for loop formation will be in- 15 terfered with by those elementsthat substantially depart from such longitudinal alinement.

It has been found that in order to produce a material fully inaccordance with the present invention, the elements should besufficiently flexible to allow the loops to form and to twist normal tothe machine direction while being formed under the action of theadhesive consolidating and gathering blade 38. Thus, neither stifistrands which do not loop under the action of the gathering blade 38,nor multiple strand yarns in which the lay of the strands opposes thetendency of the loops to twist while being formed under the action ofthe blade, Will satisfactorily serve as elements of the base web 14 whenit is desired to produce a fabric fully in accordance with the presentinvention.

It will, therefore, be seen that the features of the finished fabric aredetermined by the characteristics of the particular elements used in theformation of the base web 14 and, to some extent at least, by the natureof the process used in forming the base web.

Additional preliminary steps in the formation of the base web 14, aswell as subsequent steps for processing the fabric 40 after it flowsfrom the gathering blade 38, may be optionally carried out to alter thecharacteristics of the finished fabric.

Referring to FIG. 1, the base web 14, as has been previously described,may be formed of webs from two drafting frames 12, 25 supplied withstaple length fibers or monofilaments. Patterns of color or of fiberswhich differ from the main constituent of the fabric maybe introducedinto the finished fabric 40 by utilizing certain preliminary steps inthe formation of the base webs.

For example, the underweb from the first drafting frame 12 may be madefrom fibers of a solid color while at spaced intervals across the baseweb 14a bands of one or more colors may be introduced by passing coloredfibers through the second draw frame 25 so that the colored fibers arelaid on the underweb 14a. The top layer 14b of fibers may be applied inthe pattern desired and, it has been found, will effectively screen outthe underweb color in most instances so that the finished material willdisplay a striped appearance.

The top layer 14b of fibers from the draw frame 25 may also beintroduced in a wavy or saw-tooth pattern to produce either a wavy orsaw-tooth effect completely across the fabric, as illustrated in FIG. 2,or in bands across the fabric as desired.

Alternatively, the under layer 14a of the base web 14 may embodydifferent colored fibers by having the fibers at the margins, forexample, of one color while the fibers across the center of the web areof a different color or colors. To this end, different colored fibersmay be introduced through either or both draw frames 12 and/or 25. Thetop layer of fibers may be in the form of spaced bands of fibers acrossthe web, or the different color may be introduced through only thesecond draw frame 25 by laying down a uniform layer of fibers in whichat least certain of the adjacent slivers are of different colors. Wherethe top layer of the base web comprises spaced bands of fibers, it willbe appreciated that the finished fabric will have a varying weightacross the web, with a double weight and a more dense mass of loops inthe bands where the top fibers are laid down.

Other procedures may be used for introducing patterns into the finishedfabric. For example, a layer of fibers in the form of a section of a webfrom the second draw frame 25 may be laid on a web from the first drawframe 12 or onto a carded web underlayer. Due to the consolidationoperation performed by the gathering blade 38, the pattern will beshortened lengthwise but not appreciably disarranged laterally, suchthat whatever the pattern introduced into the top layer of the base web14, it will appear in the finished fabric in its fore-shortened form. Apattern of fibers may be introduced into the top draw frame 25, whichwill operate to aline the fibers and will draw or extend the pattern inthe machine direction. The subsequent shortening effect by the gatheringblade 38 will tend to reduce the pattern to its original form in thoseinstances where the extent of the draw in the drafting frame25illustratively l5:1is approximately the same as the take-away ratio.

As shown in FIGS. 1 and 10, the fabric 40 is carried along the take-awaysurface 41 by the action of the conveyor 52. Since the adhesive backingis hot and tacky as the fabric flows onto the take-away surface 41, thatsurface may be treated with a non-stick or release coating to insurethat the fabric may be drawn smoothly along the surface.

To cool the belt of the conveyor 52 and prevent it from becomingoverheated from the hot adhesive back of the fabric 40, streams of airmay be blown against the underside of the belt from suitably placed airnozzles 54. This will also serve to cool the fabric 40, although it maybe necessary or desirable to pass the fabric through a cooling stationor zone (not shown) to cool the adhesive and thermoplastic fibers totemperatures below their softening temperatures or to eliminatetackiness of the adhesive.

The second printing of adhesive A further method step in the productionof a high-loft fabric is disclosed in copending application of HerbertG. Minshell, Robert J. Stumpf, and William J. Mattes, Ser. No. 77,840,and basically involves the application of a second adhesive pattern uponthe first applied open pattern of adhesive.

Referring to FIG. 10, an exemplary apparatus is shown for applying thesecond adhesive pattern to the base web, with the apparatus beingsuitably inserted between portions of the apparatus shown in FIG. 1after the web is passed over roller 31 and before it reaches the drum37. The exemplary apparatus includes a first cooling station 92 forcooling the web and first adhesive pattern applied thereto, an adhesiveapplicator station 94 substantially similar to the adhesive applicationportion of the apparatus shown in FIG. 1, a curing roller 96 similar tothe roller 29, and a second cooling station 98 for cooling the web priorto its traveling to the drum 37. The printing roller of the adhesiveapplicator station 94 also has an intaglio patterned surfacesubstantially similar to the printing roll 20 shown in FIG. 1, so thatthe second adhesive pattern is applied to the first pattern of adhesive.In the event additional detailed information is desired concerning themethod of its application, reference is made to the above mentionedcopending application.

The double printing of adhesive on the fiber web may offer distinctadvantages in the resulting fabric, depending upon the particularfibers, threads, or the like that are being used. For example, assumingthat wall covering material is to be produced incorporating relativelyheavy denier fibers, as well as yarns, threads or the like that haveeither single or multiple threads, the double printing of adhesive inmany instances insures the secure attachment of the ends of the loopswithin the adhesive backing, but does not interfere with the proper loopformation during the consolidation stage of the method. As iscomprehensively described in the above copending application, thephysical thickness of a single pattern of adhesive may be increased onlyto a degree. Also, the adhesives being applied to the web may bedifferent with each of the different adhesives having characteristicscontributing to a better quality fabric. For example, the adhesiveapplied in the first pattern may be characteristically adapted toenhance the fiber holding or retaining capabilities, while the secondadhesive applied to the first pattern may have qualities whichcontribute to better consolidation during the adhesive consolidating andfiber looping step.

Thus, it is seen that for particular types of fibers, threads or thelike that are incorporated into the base web, the

17 double printing of adhesive step may be advantageously utilized.

The manufacture of high loft nonwoven fabric in accordance with thepresent invention Thus far, the environment of the invention has beendescribed in connection with methods of making high-loft, nonwovenfabrics by preparing a base comprising an open pattern of adhesive and aplurality of fibers or similar flexible elements extending generallylongitudinally thereof and bonded thereto; and, thereafter, (1)reactivating the open pattern of adhesive in which the fibers areembedded; and (2) consolidating the adhesive into a backing layer, while(3) simultaneously looping the portions of the fibers spanning the openspaces of the adhesive pattern outwardly from the backing layer formedby the consolidated adhesive.

In accordance with the present invention, provision is made for forminghigh-loft, nonwoven fabrics possessing substantially all of theattributes and characteristics of the fabrics hereinbefore describedprior to being subjected to added method steps, yet which are furthercharacterized by their unique visual appearance which is the result ofthe added method steps which change the structure of the individualloops subsequent to their formation. Also, method steps will hereinafterbe described for preparing the fiber web that is applied to the openpattern of adhesive, wherein the color and design or pattern of thefiber web may be changed during its formation by variation during one ormore of three different steps.

The method of altering the structure of fiber'loops Referring to FIG.13, an exemplary apparatus is illustrated for at least partiallyflattening or crushing the loops that were formed during theconsolidation step. The apparatus is adapted to be in-line part of theapparatus of FIG. 1 and includes, downstream of the take-away conveyor52, a heated roll 90 and a backup roll 92 which form a nip for at leastpartially flattening the fiber loops of the consolidated fabric 40. Itis to be noted that the fabric 40, while shown to pass directly from thetakeaway conveyor 52 to the nip formed between the rollers 90 and 92,may be wound for storage or transport immediately after having beenconsolidated and may be subsequently passed through the nip at a latertime by originating from the supply roll 94 shown in phantom. After thefabric 40 has been passed between rollers 90 and 92, it may be woundinto a roller by the winder 96 or the like.

To at least partially flatten or crush the loops extending outwardlyfrom the backing layer, the heated roller 90 is heated to a temperatureapproximating 375 F. which operates to soften or partially reactivatethe adhesive backing to a somewhat tacky state. Depending, of course,upon the production speed of the fabric passing by the heated roll and aparticular adhesive being used, the temperature of the heated ro'll mayaccordingly be varied. The temperature should be suflicient, however, tosoften the adhesive to the extent that the portions of the fiber loopsembedded therewithin may be angularly changed with respect to theirangular orientation approaching the nip.

In accordance with another aspect of the present invention, the backuproller 92 in conjunction with the heated roller 90 form a pressure nipwhich may be varied within limits by suitable apparatus. The nippressure may vary between the limits of about 50 p.l.i. (pounds perlined inch) to about 250 p.l.i. It has been found that increasing thenip pressure inversely affects the intensity or brightness of the colorof the resultant fabrici.e., the visual appearance of the fabric becomesmuted or dulled as the nip pressure is increased. It has been observedthat the color of fibers used in forming the slivers; for example, tendto produce a high-loft fabric 40 that is considerably brighter than thecolors of the original fibers. This effect is inherent in the basicproduction of the high-loft, nonwoven fabric 40. The partial crushing orflattening of the loops of the fabric tends to dull the color of thefabric being discharged from the nip, and the color closely resemblesthe color of the original fibers when the nip pressure approximates 250p.l.i.

As seen in the photographic reproductions of FIGS. 21, 23, 25, 27, 29and 31, the ends of the loops embedded within the adhesive are at anangle relative to a vertical plane and the loops tend to remain in theirpartially flattened state as a result of the heating of the adhesive andthe pressure being applied. The adhesive backing is then cooled to resetthe adhesive to lock the fiber loops in their partially flattenedconfiguration.

FIGS. 19 and 20, respectively, are photographic reproductions of ahigh-loft, nonwoven fabric that was produced by the apparatus shown inFIG. 1, taken as a cross section in the machine direction and magnified13 and 50 times. These figures have been included for comparison withFIGS. 21 and 32, which are similar photographic reproductions of fabricsproduced according to the method of the present invention. The fabricswere encapsulated in a transparent material which was subsequentlyhardened and cut into very thin slices which were thereafterphotographed and enlarged by a factor of 13 or 50.

Referring to FIG. 1 is shown as having the outwardly extending loops Eand F secured to the adhesive backing, indicated generally at G. Aspreviously stated, the loops tend to twist through an angleapproximating resulting in an abundance of dots or points as are shownin FIG. 19 which is a cross sectional view taken in a plane parallel tothe machine direction of the fabric. FIG. 20 is a greatly enlargedphotographic reproduction of a portion of FIG. 19.

As previously mentioned, FIGS. 21-32 are photographic reproductions offabrics produced according to the method of the present invention. FIGS.21-24 are reproductions of a fabric produced by subjecting the highloftfabric 40 to a nip pressure of approximately p.l.i. Similarly FIGS.25-28 are reproductions of a fabric sub jected to a nip pressure ofapproximately p.l.i. and FIGS. 29-32 are of a fabric that has beensubjected to a nip pressure of aproximately 250 p.l.i. As may be clearlyseen in FIGS. 21, 25, and 29, the increased nip pressures result in athinner, more compact and compressed fabric. The fabric shown in FIG. 29(nip pressure of 250 p.l.i.) is compressed a greater amount than thefabric shown in FIG. 25 (190 p.l.i.) and, similarly the fabricillustrated in FIG. 21 (100 p.l.i.) is thicker than either of theothers.

Fiber card and breaker frame blending of the original fiber webVariation of the color of a resulting fabric, in terms of the blendingof fibers as well as the forming of a fiber web having a predeterminedpattern, is of course desirable for many of its potential applications.In the preceding background of the invention, methods were described forproducing some color variation of the basic high-loft nonwoven materialas is seen in FIGS. 2 and 3.

In accordance with another aspect of the present invention, method willnow be described which permit great flexibility in the formation of thefiber web that is applied to the open pattern of adhesive, in which agreat variety of color blends as well as predetermined designs may beimparted to the fiber web.

Turning now to FIG. 14, a schematic block diagram is illustrated andshows the steps performed to produce a striated fiber web such as web14a shown in FIG. 1. It is to be noted that the draw frame 12 isintended to be the same as draw frame 12 of FIG. 1 and may be identicalto the draw frame 25 as well.

Supply cans 100 each contain a continuous sliver of fibers that havebeen formed from a bat 0f fibers by conventional carding techniques orthe like. The slivers are guided by the creel 102 to a breaker frame 104which operates to draw the slivers to increase their length as well asto combine them into a number of groups of slivers which are in turnguided to anothed draw frame 12 by the creel 106. The draw frame 12again draws the groups of slivers to further increase their length aswell as combine them to form a relatively flat striated fiber web thatis subsequently applied to the open adhesive pattern.

As previously mentioned, the slivers in the supply cans 100 may becomprised of fibers of one or more colors. In the event various coloredfibers are combined to form a homogeneous mix before the slivers areformed, it is recognized that the slivers will include all of the colorsoriginally introduced. Thus, it is seen that the relatively smallslivers may have a variety of color blends.

In accordance with another aspect of the present invention, the creel102 may combine a number of slivers, for example 8 slivers, into a groupof slivers that is fed into the breaker frame 104. By selectivelycombining the slivers, the group of slivers may be given a dominantcolor by combining, for example, six slivers of one color and twoslivers of another. The resultant dominant color of a particular groupof slivers may be different from either of the two colors of sliversthat are combined to form the group. Similarly, it is seen that in theevent multiple fibers were introduced to form the original slivers, theselective combination of those slivers with slivers of other colors mayresult in a group having a color that is variable within a very widerange.

Still another aspect of the present invention is the fact that thegroups of slivers are guided by creel 106 for introduction into the drawframe 12 where further drawing of the groups of slivers is performed andthe groups are combined to form the flat striated fiber web. It is seenthat by selective combination of the groups of fibers having a dominantcolor, a fiber web may be formed that has a predetermined design acrossits width. Thus, it is seen that a great variety of color blending maybe achieved through variation of the colors of the fibers within theoriginal slivers, by the selective combination of slivers to form thegroups of slivers, and also by the selective combination of the groupsforming the fiber web.

Yet another aspect of the present invention involves the combining ofthe groups of slivers in the machine direction. One end of the group ofslivers, for example, may be tied to an end of another group to form onecontinuous group. If the second group has a dominant color differentfrom the first, the resulting fiber web (and thereafter the resultinghigh-loft, nonwoven fabric) will not have a continuous color in themachine direction in those 'areas where the tieing occurred.

As an example, a high-loft, nonwoven fabric was produced by using themethod of the present invention wherein four colors of rayon staplelength fibers, namely, spice brown, marigold, champagne and sea greenwere blended into a homogeneous mix of fibers prior to the carding ofthe fibers into slivers. The original carded slivers each weighed about68 grains per linear yard. The sliver was then put through the breakerframe 104 and blended with other slivers as well as drawn to produce asliver having a weight of about 35 to 38 grams per linear yard. Eight ofthese drawn slivers were fed into the breaker frame 12 to form a groupof slivers which were then combined with other groups of slivers to forma flat striated web that was applied to the open pattern of adhesive.After going through the fiber looping and adhesive consolidation step,the fabric was then passed between the heated and pressure producing nipto partially flatten or crush the outwardly extending loops. Theresulting product was characterized 'by a flexible adhesive backing anda somewhat coarse surface texture having a mottled appearance with theloops being partially flattened. Although four colors of fibers wereoriginally used, the resulting color of the product was generally of alight muted brown appearance. The presence of the different colors incombination with the crushing of the material appears to contribute tothe appearance of the conventional woven crushed velvet, in that thebending of the fabric changes its visual appearance within the creasesand folds. Generally as the angle the fabric was viewed approached byplane of the fabric, the fabric gave the visual appearance of becominglighter.

Another example involved forming a number of single color slivers fromfibers of marigold, bittersweet and gold fibers. The slivers were thencombined in groups containing either four marigold and four gold sliversor in groups having six gold and two bittersweet slivers. The drawing ofthe individual slivers as well as the groups of slivers weresubstantially similar to the example hereinbefore described. The groupsof slivers were then combined in the draw frame 12 in a predeterminedmanner so that the resultant fiber web had a variable striped designacross its width. The fiber web was applied to the adhesive pattern, andwas passed through the fiber looping and adhesive consolidating stationas well as through the heated pressure nip. The resulting product wascharacterized by a surface texture substantially similar to the examplepreceeding, and had a striped appearance wherein the stripes were eithera very dull yellow, a very dull orange, or a somewhat brighter orange.The width of the stripes were non-uniform which appeared as almost solidcolors in some areas and relatively thin mottled stripes in other areas.Where the stripes were very thin, the stripes had the appearance of notbeing straight and continuous in the machine direction. Additionally,the product also resembled the crushed velvet effect as described in thepreceding example.

I claim:

1. A method for producing a high-loft, nonwoven fabric, which comprises:

preparing a web including flexible elements extending longitudinally ofthe Web;

bonding the elements in an open pattern of adhesive;

reactivating the adhesive to a tacky state;

consolidating the open pattern of tacky adhesive at a consolidatingstation (i) to form a backing layer (ii) while looping the elementportions located in the open spaces of the adhesive pattern outwardlyfrom the backing layer; conveying the consolidated adhesive backinglayer and outwardly looped elements away from the consolidating station;and

reactivating the adhesive within the backing layer to a tacky state andapplying pressure to the looped elements whereby the looped elements arepartially flattened and the portions of the looped elements within theadhesive are reoriented whereby the looped elements are maintained intheir partially flattened configuration.

2. The method claim 1 wherein the elements of the web are staple lengthfibers.

3. The method of claim 1 wherein the elements are selected from a groupconsisting of synthetic yarns, natural yarns, synthetic threads, naturalthreads or blends thereof.

4. The method of claim 1 wherein the open pattern of tacky adhesive issubstantially fully consolidated to form a substantially continuousbacking layer.

5. The method of claim 1 wherein the open pattern of adhesive comprisesa series of interconnected diamonds.

6. The method of claim 1 wherein reactivation of the adhesive to a tackystate is achieved by carrying the web onto a heated surface, and

consolidation of the open pattern is achieved by impinging the elementsand the tacky adhesive against the edge of a relatively moving gatheringblade.

7. The method of claim 1 wherein a second open pattern of secondadhesive is applied to the first applied 21 open pattern of adhesive,the second pattern being substantially similar to the lfirst appliedpattern, the second pattern of adhesive being applied subsequently ofbonding the elements in the first applied pattern of adhesive.

8. The method of claim 7 wherein the elements are bonded in the secondpattern of applied adhesive.

9. The method of claim 1 wherein reactivation of the adhesive backing isachieved by passing the adhesive backing and outwardly looped elementsbetween a heated roll and a back-up roll.

10. The method of claim 9 wherein the heated roll has a temperature ofat least about 375 F.

11. The method of claim 9 wherein the heated roll and back-up roll forma nip, with the nip applying a pressure to the adhesive backing andoutwardly looped elements within the range of about 50 p.l.i. to about250 p.1.i.

12. The method of claim 1 wherein the preparation of the Web comprises:

forming a plurality of slivers from a multiplicity of combining theslivers at a predetermined pattern to form a number of groups ofslivers;

drawing the groups of slivers to increase their length;

and,

combining the groups of slivers in a second predetermined pattern toform a flat striated web.

13. The method of claim 12 wherein the multiplicity of fibers arehomogeneous mix of fibers selected from fiber supplies of one or morecolors.

14. The method of claim 13 wherein the individual slivers within thegroups are selected to impart a dominant color to each of the groups.

15. The method of claim 14 wherein the groups of slivers having adominant color are combined within the striated web to impart apredetermined design to the web.

16. A method for producing a high-loft, nonwoven fabric, comprising:

preparing a web including flexible elements extending longitudinallythereof;

bonding the elements at spaced points in a pattern of adhesive;

feeding said web onto a smooth movable surface with said adhesive incontact with said surface, heating said adhesive to a tacky state sothat it adheres to said surface, carrying said web on said surface tothe edge of a gathering blade and impinging said elements and tackyadhesive against the edge of said gathering blade to loop the portionsof said elements spanning the spaced points outwardly from said web andto consolidate said adhesive into an adhesive backing layer;

conveying said adhesive backing layer and outwardly looped elements awayfrom said surface and said gathering blade; and

while the adhesive in the backing layer is in a tacky state, applyingpressure to partially flatten the outwardly looped elements and toreorient the portions of the looped elements within the adhesive backinglayer to maintain said outwardly looped elements in their partiallyflattened condition.

References Cited UNITED STATES PATENTS 2,550,686 5/1951 Goldman 156-4712,639,250 5/ 1953 Reinhart 161-65 3,214,323 10/ 1965 Russell et al16114O 3,220,056 11/ 1965 Walton 1819 3,236,718 2/1966 Cohn et a1161--128 ROBERT F. BURNETT, Primary Examiner R. O. LINKER, JR.,Assistant Examiner US. Cl. X.R.

